This study examines the ways in which environmental liability for environmental harm is allocated under Hungarian laws and regulations and in the practice of domestic courts. Specifically, it focuses on how laws handle the uncertain nature of causal links between a given pollution and its possible source, and which actors should bear the costs of remediation. The study posits that the uncertain nature of scientific evidence impacts the way environmental liability can be allocated and enforced, as scientific evidence can never establish requisite causal links with absolute certainty. The article first enumerates and discusses the sources of scientific uncertainty and demonstrates that it inescapably burdens scientific evidence. It then examines how laws and regulations in force handle causal uncertainty and the ways in which liability for environmental harm is distributed among various actors. The study concludes with proposing legislative amendments in order to allocate environmental liability in a more equitable way in cases when the causal processes remain inherently uncertain.